1. Field of the Invention
The present invention relates to track-mounted vehicles and, more particularly, is directed to suspension apparatus for vehicles that are adapted to travel on rails.
2. Description of the Invention Background
According to the American Railroad Association, there are approximately 173,000 miles of actively used railroad tracks in the United States. In addition to locomotives and the haulage cars that they tow, a variety of other vehicles have been developed for riding the rails to perform various maintenance and inspection functions. For example, mobile vehicles have been developed to ride along the tracks and cut brush and vegetation adjoining the railroad right of ways. Examples of such vehicles are disclosed in U.S. Pat. No. 5,392,593 entitled Mobile Apparatus for Cutting Vegetation and pending U.S. patent application Ser. No. 08/615,418, filed Mar. 14, 1996, entitled Vegetation Cutting Apparatus, the disclosures of which are herein incorporated by reference.
Track-mounted vehicles of the type described above and other track-mounted vehicles can, at times, experience derailment when the vehicle contacts a switching mechanism which serves to direct the vehicle onto another set of adjoining rails. For example, some switches, due to their design or location, can cause the rear set of wheels to derail from the track as the vehicle traverses the switch. Such derailment can cause that section of track to be closed for longer than normal maintenance periods. In addition, such derailments can cause injury to personnel and damage the tracks and the vehicle itself.
While sophisticated suspension systems have been developed over the years for various vehicles, such systems are often expensive to install and maintain making them illsuited for use with some track-mounted vehicles. Thus, there is a need for a suspension system for a track-mounted vehicle that is relatively inexpensive to install and maintain.